I agree, everyone thinks cars, bikes, buses, and people all should follow the same line along the same corridor. Having bike lanes seperated more can be very benefecial and helps seperation without need for physical barriers. For example a road could run down the center of a commercial area, with a dedicated BRT lane, and bike/ped pnaes closer to the businesses or even a seperate enterance/laneway behind the businesses dedicated to people.
But most of North America thinks a painted bicycle gutter along a busy road, crossing many car intersections and entrances is the best we can build.